typedef int KEY_TYPE;typedef struct _rbtree_node
{unsigned char color;struct _rbtree_node *left;struct _rbtree_node *right;struct _rbtree_node *parent;KEY_TYPE key;void *value;
}rbtree_node;
左旋实现
void _left_rotate(rbtree *T, rbtree_node *x)
{rbtree_node *y = x->right;x->right = y->left;if (y->left != T->nil){y->left->parent = x;}y->parent = x->parent;if (x->parent == T->nil){T->root == y;}else if (x == x->parent->left){x->parent->left = y;}else if (x == x->parent->right){x->parent->right = y;}y->left = x;x->parent = y;
}
右旋实现
void _right_rotate(rbtree *T, rbtree_node *y)
{rbtree_node *x = y->left;y->left = x->right;if (x->right != T->nil){x->right->parent = y;}x->parent = y->parent;if (y->parent == T->nil){T->root = x;}else if (y == y->parent->left){y->parent->left = x;}else if (y == y->parent->right){y->parent->right = x;}x->right = y;y->parent = x;
}
将新节点的颜色设为红色,然后按照二叉查找树的规则插入到合适的位置
如果设置成黑色的话,则必定会违反上述五条性质中的第五条
如果新节点是根节点,那么将其颜色改为黑色,结束
如果新节点的父节点是黑色,那么不需要做任何调整,结束
如果新节点的父节点和叔叔节点(父节点的兄弟节点)都是红色,那么将它们的颜色改为黑色,将祖父节点(父节点的父节点)的颜色改为红色,然后把祖父节点作为新的当前节点,重复步骤2和3
如果新节点的父节点是红色,但叔叔节点是黑色或不存在,那么分四种情况进行旋转和变色操作:
int key_compare(KEY_TYPE *a, KEY_TYPE *b)
{//TODO
}void rbtree_insert_fixup(rbtree *T, rbtree_node *z)
{while (z->parent->color == RED){if (z->parent == z->parent->parent->left){rbtree_node *y = z->parent->parent->right;if (y->color == RED){z->parent->color = BLACK;y->color = BLACK;z->parent->parent->color = RED;z = z->parent->parent;}else{if (z == z->parent->right){z = z->parent;_left_rotate(T, z);}z->parent->color = BLACK;z->parent->parent->color = RED;_right_rotate(T, z->parent->parent);}}}T->root->color = BLACK;
}void rbtree_insert(rbtree *T, rbtree_node *z)
{rbtree_node *x = T->root;rbtree_node *y = T->nil;while (x != T->nil){y = x;// 如果是自定义类型,可以实现key_compare接口来进行比较if (x->key > z->key){x = x->right;}else if (x->key < z->key){x = x->left;}else{return;}}z->parent = y;if (y == T->nil){T->root = z;}else if (z->key > y->key){y->right = z;}else{y->left = z;}z->left = T->nil;z->right = T->nil;z->color = RED;rbtree_insert_fixup(T, z);
}